Positive blade rotation arrangement for disconnect switch

ABSTRACT

A cam guide on the stationary contact portion of the disconnect switch cooperates with a hook follower on the rotary blade. The hook follower operates to control the rotation of the blade only when the blade has made positive positioning engagement with the contact. The cam and follower arrangement also insures that the blade is orientated to correct angular position as the blade is bodily rotated to the open position. A contact housing is provided for the current carrying contact fingers which mounts the contact fingers and also serves as an ice and rain shield with corona protection also being provided by the housing.

United States Patent Redfern [451 Sept. 17, 1974 3,134,865 5/1964 Bernatt 200/48 SB Primary ExaminerRobert K. Schaefer Assistant ExaminerM. Ginsburg [75] Inventor: Calvin E. Redfern, Portland, Oreg. Attorney, Agent, or FirmfiRobert C. Jones [73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis. [57] ABSTRACT [22] Filed: July 1973 A cam guide on the stationary contact portion of the [21] Appl. No; 379,802 disconnect switch cooperates with a hook follower on the rotary blade. The hook follower operates to control the rotation of the blade only when the blade has [2%] 98.3] 200/48 AiOOMti SE0 made positive positioning engagement with the [5 1 .f 3 Contact The Cam and follower arrangement also 8] 0 ZOO/48 48 g sures that the blade is orientated to correct angular 200/ 8 S position as the blade is bodily rotated to the open po- 56 R f d sition. A contact housing is provided for the current 1 e erences carrying contact fingers which mounts the contact fin- UNITED STATES PATENTS gers and also serves as an ice and rain shield with co- 2,753,407 7/1956 Hollander ZOO/48 A rona protection also being provided by the housing. 2,760,019 8/1956 Curtis ZOO/48 SB 2,810,799 10/1957 Carmichael et al. zoo/4s SB 3 Clam, 9 Drawmg; Flgures V v I! I j 3 \Z! I J02 g4{\ PAIENIEB SEP 1 mm SHEET 3 OF 3 POSITIVE BLADE ROTATION ARRANGEMENT FOR DISCONNECT SWITCH DESCRIPTION OF RELATING PRIOR ART links from collapsing until such timesas the bodily rotation of the switch blade is stopped by a stopmember.

Thereafter the rotations of the drive spindle. cause -.a crank to shift the position of the coupled links. "with the collapse of the links the gear drive is free to effect rotation of the switch blade about its axis.

In US. Pat. No. 3,134,865, rotation of theblade about its own axis is effected through a follower arm that is connected to the blade .and to .a drive member. As the blade assembly is prevented from rotating about a vertical axis the drive member continues tonrotate forcing the follower arm to move with it. This-move merit of the follower arm causes the blade to rotate about its own axis. This is due to the clampconnection established between the'follower arm and theblade. With this condition obtained, a follower disc under influence of a spring, rides a cam groove from a detent position onto a flat surface of a cam. Thus, both-the bodily rotation of the blade assembly and the rotation of the blade about itsown axis are accomplishedsolely through the drive effort obtained from the insulator.

It is apparent that those skilled in the art had no concept or thought of providing means on the stationary contacts at a point most remote from the driving insulator to effect angular positioning of the blade .ar-m about its own axis which means insures positive positioning of the blade both in an .opening movement and in a closing operation.

BACKGROUND OF THE INVENTION with positive engagement between the blade and the stationary contact assured.

Disconnect switches of the type to which the invention relates have the blade mounted for rotation about a vertical axis to open or closed positions. Rotation of the blade requires a considerable actuating force so as to overcome the inertia of the structural massandalso to compensate for a considerable ice load which :these types of switches are subjected to. Notonly are mass and ice loads a factor in actuating .thesetypes of switches, but proper and correct engagement of the blade with the stationary contact is a factor which must be considered. This factor depends largely on blade angular orientation as it is rotated from open to closed position. Thecorrect angle of approach of the bladewith respect to the stationary contact must be established prior to the engagement of the blade with the contact. This is true because misalignment of the blade with respect to the stationary contact will result either in the closing of the switch not being effected or a proper blade and contact engagement will not be accomplished. Also with these types of switches ice on the blade is a considerable factor. In a closing operation the impact of the blade against the contact structure has, .in the past, been relied on to dislodge or break the ice coating on the blade. T he additional actuating force required to effect sufficient impact of the blade with the contact structure to dislodge or break ice on the blade also imparts an extremely severe shock load to the structure which has been known to cause structural blade for contact engagement.

A further objectof the invention is to provide a disconnect switch having a cam follower arrangement which engages cam means on the contact structure to effect the pivotal movement of the blade into proper orientation with the contact structure.

A further object of the inventionis towprovide a contact structure including a housing which serves both :as an .ice protector and a corona shield.

A still further object of the invention is to provide a cam follower which is constructed and. arranged to transmit torque to and from the blade.

Yet another object of the invention is to provide the blade of a disconnect switch with cam means which is operable to rotate the blade about its own axis, prior to the blade being bodily rotated to an open position to thereby orientate the blade to a desired angular position for a subsequent closing engagement.

' disconnect switch in which the invention is incorporated;

FIG. 2 is a plan view of the disconnect switch of FIG. 1; FIG. 3 is an enlarged detail fragmentary view of the right-hand stationary contact showing the disconnect switch blade in engagement therewith;

FIG. 4 is an enlarged side view of the right-hand contact of FIG. 3, showing the orientation of the switch blade in contact with the stationary contact structure;

FIG; 6 is a view similar to FIG. 5 illustrating the position "of the blade and cam mechanism as it appears when the blade has made complete full engagement with the stationary contact structure;

FIG. 7 is an enlarged fragmentary view partly in elevation and partly in section showing the blade assembly support and a portion of an extending arm;

'FIG. 8 is a view in vertical section through the blade arm taken in a plane represented by the line VIII-VIII in FIG. 7, showing the arrangement for maintaining the blade tube in a desired angular position; and,

FIG. 9 is a view in horizontal section through th lever arm pedestal support taken in a plane represented by the line IX-IX in FIG. 7 showing the positive stop arrangement.

DESCRIPTION OF THE INVENTION FIG. 1 illustrates a preferred embodiment of the invention which comprises a rotating blade assembly 10. The rotating blade assembly 10 is a single current carrying tube 11 which is mounted in bearing housing 87 and which, in turn, is mounted on an insulating column 17. The tube 11 extends outwardly of the housing 87 to present arms 12 and 14. The insulating column 17 is rotatable about its own longitudinal axis and is mounted upon the convenient base 18. Also positioned on the base 18 are the stationary switch contact insulators 19 and 21 which are rigid and stationary and are also mounted on the base 18 as shown. Mounted to the fixed switch contact insulators l9 and 21 are the fixed contact assemblies 26 and 27, respectively. The fixed contact assemblies 26 and 27 are mounted to face in opposite directions so as to provide for the engagement of the blade arms of the rotating blade assembly 10. As shown in FIG.'2 the rotating blade assembly 10 rotates from an open position to a closed position in a counterclockwise direction as indicated by the directional arrow A, as viewed in FIG. 2. Each of the fixed contact assemblies 26 and 27 are provided with terminal lugs 28 and 29, respectively, to which appropriate electrical power lines may be attached. An electrical circuit is completed through the terminal lug 28, the fixed contact assembly 26, the tube 11 of the rotating blade assembly 10, through the fixed contact assembly 27 and thence through the terminal lug 29. Circuit isolation may be provided by rotating the insulating column 17 in a clockwise direction, as indicated by the directional arrow B in FIG. 2, thus effecting rotation of the blade assembly 10 out of engagement with the fixed contact assemblies 26 and 27.

To facilitate good electrical contact between the rotating blade assembly 10 and the fixed contact assemblies 26 and 27 the ends of the extending blade arms 12 and 14 are provided with flattened or somewhat elliptical end contact portions or blade plugs 31 and 32, respectively. The blade plugs 31 and 32 on the ends of the arms 12 and 14 provide for maximum clearance between the blade plugs and the associated stationary contact assemblies as the blade assembly is rotated in a closing movement. The maximum clearance between the blade plugs 31 and 32 and the associated stationary contact assemblies together with the considerable rotational closing force insures entrance of the blade plugs into the associated stationary contact assemblies even if the assembliesare coated with ice. r

As shown in FIGS. 2, 3, and 5, the elliptical or flattened end portion or blade plug 31 of the arm 12 is provided with longitudinally extending upper and lower rib portions 38 and 39 which extend the entire length of the flattened portion 31 thereof. The rib portions 38 and 39 on the arm 12 insure that good electrical contact will be made between the blade and the resilient upper and lower contact fingers 41 and 42, respectively, of the stationary contact 26. The contact end of the arm 14 is constructed in identical fashion to the arm 12 and thus has a flattened or somewhat elliptical end contact blade plug portion 32 likewise provided with the upper and lower longitudinally extending rib portions (not shown) to insure good electrical contact with resilient fingers (not shown) associated with the stationary contact 27. Thus, after the rotating'blade assembly 10 has been rotated so as to engage the blade plugs 31 and 32 thereof with the fixed contacts 26 and 27, respectively, the blade tube 11 will be rotated about its longitudinal axis so that the rib portions 38 and 39 of the blade plug 31 engage against the resilient contacts 41 and 42 of the stationary contact assembly 26. A similar condition obtains between the contact blade plug 32 and the associated stationary contact 27.

The description of the construction and operation of the stationary contact 26 and the associated arm blade plug31- will also apply to the stationary contact 27 and the associated blade plug 32. However, it will be appreciated. that the arrangement of the components associated with the stationary contact assembly 27 will be inverted to accommodate for the rotation of the tube 11. With reference to FIG. 3, the blade tube 11 is supported in a housing or cradle 87 for rotation about its own axis. This rotation of the blade tube 11 about its own axis is efiected when the contact blade plugs 31 and 32 of the arms engages the stationary contact assemblies 26 and 27, respectively. To this purpose, a cam mechanismSl is secured to the axial end of the arm 12. The cam mechanism 51 is arranged to cooperate with a cam track and ice breaker structural side 52 of the stationary contact 26. As the contact blade plug 31 enters the stationary contact assembly 26, the angle of the blade plug 31 is approximately 75 from the vertical plane. Thus, the blade plug 31 is free to enter the gaping mouth 53 of the stationary contact assembly 26 under the rotational impetus from the center support insulator 17. As the blade plug 31 enters further into the stationary contact assembly 26, the cam mechanism 51 engages with cam track structure 52 and in cooperation therewith effects rotation of the blade tube 11 about its axis. This movement will cause the blade tube 11 to rotate in a counterclockwise direction, as viewed in FIG. 5. Upon complete entrance of the blade plug 31 into the stationary contact assembly 26, the blade plug will have been rotated to a vertical position wherein the upper and lower rib portions 38 and 39 thereof firmly engage with the plurality of upper and lower resilient contact members 41 and 42. This is true because the tubular portion 513 will follow the upwardly sloping guide surface 71C thereby rotating the blade plug 31 and its associated blade 11 in a counterclockwise direction, as viewed in FIGS. 5 and 6.

. As the blade plug 31 enters the stationary contact assembly 26 any ice that may have formed either as icicles or asa curtain will be broken. Also as the cam mechanism Slengages with the cam track structure 52 ice on the cam mechanism and the track structure will I be crushed. Furthermore, the rotation of the blade plug 31 within the stationary contact assembly 26 under the positive rotational force of the cam mechanism 51 and cam structure 52 will effectively crush and wipe clear any ice that might be accumulated on the resilient contactst4'l and 42.Thus, positive electrical engage.-

ment v between the blade plug 31 and the resilient.

contact fingers 41 and 42 is ensured.

In addition, when the blade assembly is rotated to. an open position the angular positioning movementof the blade plugs 31 and132 is ensured. The angular orientation ofthe blade plugs 31 and 32in the opening movement is an assurance that electrical engagement between the blade plugs-31 and 32 and therespective stationary contact assemblies 26 and 27 will occur in a.

the blade plug 31-to rotate in a clockwise direction, as viewed in FIG. 6. As the blade plug 31 leaves .the,sta-- tionary contactassembly 26 it will have beennrotated; about itsow-naxistto-the position depicted in FIG; 4,

which .position will be maintained thereafter throughout the entireopening. movement of the assembly.10.-

In the positionof the blade plug 31, as depicted in FIG.

4, the proper angular orientation of the'blade plug311 is estab'lishedfor a subsequent closing movement;

Foreffecting the foregoing angular positioning move ment of the blade plug 31, the. stationary contact 26 is formed of a substantially C-shaped body 61 havinga cam track-i outerside wall 62 with which the electrical.

gers4l. Thefmgers 41 are removably secured to. the. body portion 61 in a conventional manner such as by screws (notshown). Ina similar manner the lower resilient contact fingers 42 are. likewise removably secured in spaced apart relationshipto the lower jaw of theC- shaped body.

To afford weather protection to the interior offithe. contact assembly and to the resilient contact fingers 41 and42'acap member 69'is provided. The cap member 69 is removably secured in position on the C-shaped body 61 as by screwsand lugs 198, l99and 204,205.

The forward edge 71 of thecap 69 extends forwardly so as to overhang the entrance or mouth 53 of the contact assembly 26. Thus, snow and sleetisl prevented from directly entering into the contact assembly 26.

With the. cap 69 overhanging the entrance 53 of the contact assembly 26' iceis more apt to formas icicles or a curtain over the entrance53 which may easily .be

. brokenupon impact of the'blade plug 31 therewith;

To effect therotation ofv the tube 11 and thus the blade plug 31 about its own axis, the ,cammechanism; .51 is provided. As depicted in FIGS.'3 and 4,.the cam mechanismSl is an integral member supported on the extending endof a stub shaft 72 which extends out.- wardly in coaxial.relationshipfrom the blade plug 31. The side of the cam mechanism 51 adjacent the end of theblade plug 31 is. providedwith a pair ofrearwardly' or inwardly extending spaced-apart lugs or cars 73 and. 74. .Theears 73and 74 are adapted to engage the sides.

of the blade plug 31 when-thescamv member 5 1 is mountedin operative position=on'ltherstub1vshaftt72hasr depicted" in FIGS. 3 'andi4..Thus; azforce whichtterids-- topi'vot the cammechanism 5'1 about-gthe; axis of the. blade tube l li will be transmitted 'toathe:blade plug 311 via one or -the. other ofithe. lugs 73or74 forcing the blade tube 11to rotateabout ItSwOWI'IbaXlS BI'Idithfeby effecttthaangular positioningyofi the blade:plug. 3 1.

As previously; mentioned; thecamtrack structure 52? is formed integrally. with the,;contact=hody 61, and; co-- operates .withithescam meohanismslstoeffect the rota-1 tion ofithe. bladeq-plug =3ll into the. desired. angulanposi tion. As shown inFlGS-J- .4, 5*and 6', the. cam track structure: 5251 comprises a lower horizontala projection 76 which extends outwardlyishort of the edge-of'the pedestal contact freceivihgplatefi? The .arcuate forward portion-= 76Aof the projection 1 76 serves as an 1 approach't abutmentxagainst:whioh:a tubular portion 51A oftthe cam mechanism 51 engages when .the switch assemhly. 10 is rotated to a switch'closed position. A'sstherrotati'on ofithe assembly 10.=to'switch closediposition'continues, the. tubular-portion 51A rides 'on. the top edge :76'B of the projection 76.. With this condition obtained; an upper tubularprojectiOnSlBiof the: cam mechanism 51 I engages with thesdependi'ngzcontroledgee8i of a depending guide 82 formed-integrally with'thetsh'ield 69; as. illustrated in":FIG. 5: Thus; theztwo tubular: projectionsS'lA and 5:18 in 'cooperation with thezcontrol-sun faces 76B .and8l controlnth'e angular: position: :of the i "bladeg-plug'3ltas thetblade. plugaentersiinto the. contact assembly 26. g I

As rotation of "thevassembly 10 continues. in' a :switch closing movement the blade plug 31 is-rotated to: a ver tical position to firmly; engage. thetcontact ribs: 38; 39 with the resilient *contact fingers 41; .42;-respectively.

To this end th'e cam track structure. 52 is formed with an upwardlysloping guide surface-76 Theupperver-J tical portion 176Dlof .the guideisurface r76C cooperates with-the rear vertical fedger83 of the. guide 82 to form a guide track in whichflthewupper:tubularportion 518 tracks as the blade plug-.31 moves 'furtherinto the contact assembly-2.6. As thetubular portionSlB slideson'rthe guidesurface 766, the reactionforce effects -ro-- tation of the blade tube 1 1 'andthcreforethe blade'aplug.

31, about! its .own axis. As :the. tubular: portion ilB moves-furthenupward in the: track the lower tubular portion: 51A follows along thet edge 76B and into the recess 76E. Thus", .rotation of the blade .plug 31 to a vertical position iseeffected inn.azcounterclockwise direction, as aviewed in-aFlG. 6',-- beingy-limitedby -the rear. ver-l ticaledgea83i of the-guide 81.

In amopeningmovement the blade pliig3lis rotated in1a clockwise".directions-in. a; controlled. movement. to:

orientate theblade. plug 31 from theaverti'cal fposition it occupies, as depicted.in- FIG. 6; tothe entry position, as depicted in FIGA. Thus,ithe=blade pltig131 is angularly positioned fat. the correcta-angle-cfor. Wsubsequent entry into. the stationary contact: assembly -26l -=ln' this the insulator 117, as. previously mentioned. vTo this end .7

the blade tube ".1 1 extendshthroughfasleeve 86 that is, in turn, .carried'in a cradle 87; For-supporting the. sleeve 86 for rotation about its own axis in the cradle 87, the cradle is provided at each end with bearings 88 and 89 which are seated in suitable bearing seats provided therein. A bearing lock nut 91 is threadedly engaged on the end of the sleeve 86 and operates to lock the associated bearing 88 in operative position. A similar arrangement is provided at the opposite end of the cradle 87.

The sleeve 86 with the bearings 88 and 89 serve as a rotatable support for the blade tube 11 so that it is free to rotate about its own axis relative to the cradle 87. For locking the blade tube 11 to the sleeve 86 a split collet 93 is mounted about the blade tube and is disposed in abutting engagement with the axial end of the sleeve 86. A retainer ring 94 having an axially extending flange is disposed about the collet 93 and serves to both compress the collet into tight clamping engagement with the blade tube 11 and also to retain the collet in position. To this end the wall 96 of the axially extending flange of the retainer ring 94 is of a conical configuration which is complementary to the conical external peripheral surface 97 of the collet 93. Thus, the wedging action between the flange of the retainer 94 and the collet 93 results in effecting a clamp ing of the collet about the blade tube 11. To secure the retainer 94 in position, a plurality of screws 98, one of which is shown, is provided. A similar arrangement for the opposite end of the sleeve 86 is provided.

To rotatably support the cradle assembly 87 for bodily rotation about a vertical axis, the cradle is provided with a depending conical stem 101. The stem 101 is disposed within a pedestal 102 that is bolted to the top surface of the rotatable support insulator 17. For rotatably supporting the cradle assembly 87 there is provided an upper bearing 103 which is disposed in suitable bearing seats formed in the stem 101 and the pedestal 102. A lower bearing 104 is disposed within a lower pedestal bearing seat and a bearing retainer 106. The entire assembly is maintained in operative relationship by means of a bolt and nut arrangement which is operative to clamp the assembly together.

The blade tube 11 is maintained in a static angular position relative to its own axis for maintaining the blade plugs 31 and 32 in the angularly oriented position for entry into the stationary contact assemblies 26 and 27, respectively. This position is illustrated by the position of the blade plug 31 as shown in FIG. 4. This angular position of the blade plug is maintained while the blade assembly 10 is in an open position and until such time as the blade plugs 31 and 32 engage their respective stationary contact assemblies 26 and 27. To this purpose the pedestal 102 is provided with an arm 111 that extends outwardly and upwardly towards the blade tube 11. Within the arm 111 there is disposed a leaf spring assembly 112 comprising one or more leaf springs 114. The end of the leaf spring assembly 112 adjacent the pedestal 102 extends through an opening or slot116 formed in the base of the pedestal 102. The leaf spring assembly 112 engages on a fulcrum such as a bolt or cast plug 117 carried by the arm 111. The opposite outwardly extending end of the leaf spring 'assembly 112 engages a knife edge 119 of a support pivot 121 which operates to connect the arm 111 to the blade tube 11. "T '7 j The connection to the blade tube 11 is accomplished through a short cylindrical section 122 which fits within the support pivot 121 and extends upwardly through an opening 123 provided in the arm 111. A pivot bolt 126 extends through the blade tube 111 on an axis which is angularly displaced to the right, as viewed in FIG. 8, from the vertical plane. The lower end of the bolt 126 is threadedly engaged in an ice shield 127 which also functions as a securing nut for maintaining the bolt in position. As depicted in FIGS] and 8, the ice shield 127 is elongated in the direction of the axis of the blade arm 12 and extends sufficiently far to cover the open-" ing 123 through which the cylindrical section 122ex-" tends. The longitudinal extending sides 128 and 1296f the shield 127 are sufficiently wide enough to provide an umbrella-like protection for the pivot connection, as depicted in FIG. 8. The extending end of the pivot bolt 126 is formed as a stud 130 which is engaged in a suitable bore provided in the cylindrical section 122. The assembly is such that the leaf spring assembly 112 is preloaded by means of the fulcrum stud 117. Thus, the leaf spring assembly 112 at the ends thereof develops an upwardly acting reaction force. The reaction force at the outer end of the leaf spring assembly 112 is appliedto the support pivot 121 as a vertically applied force which is transmitted to the lower end of the pivot bolt 126. This force tends to rotate the blade tube 11 in a clockwise direction, as viewed in FIG. 8, thereby maintaining the blade plug 31 in the desired angular open position that it occupies, as depicted in FIG. 4.

The angular movement of the blade tube 1 1 about its own axis is limited by operation of a positive stop means 131, FIGS. 7 and 9. To this end the lower portion of the cradle 87 is provided with a recess or slot 132 which forms abutments 133 and 134. A fixed tongue or thumb 136 formed on the pedestal 102 is disposed to engage in the slot 132. Thus, with the blade assembly 10 in the open position, as depicted in FIG. 2, the leaf spring assembly 112 is exerting an upwardly acting force on the pivot bolt 126 to urge the blade tube 11 in a clockwise direction to thereby maintain the blade plug 31 in the position it occupies as depicted in FIG. 4. In this position the tongue 136 will have been moved into engagement with the abutment 133. Since the connection between the right-hand end of the leaf spring 114 and the support pivot 121 is one of force application rather than by a fastening device, angular rotation of the blade arms 11 and 12 past a predetermined angular position could conceivably effect disengagement therebetween. This, of course, might possibly result in displacement of the cylindrical section 122, the support pivot 121 and the leaf spring assembly 112. Thus, the provision of the positive arrangement 131 insures that, with the blade assembly 10 in open position, the blade arms 11 and 12 cannot be inadvertently rotated past a predetermined angular position at any time. In this manner inadvertent dislocation of the pivot connection between the support pivot 121 and the end of the leaf spring 114 will be prevented. This is also for inadvertent rotation of the blades 11 and 12 in the opposite direction, since the surface 134 will engage the projection 136.

When the blade assembly 10 is rotated to a closed position, the tubular portion 51A of the cam mechanism 51 will engage the arcuate forward portion 76A of the projection 76. As the blade plug 31 enters further into the stationary contact assembly 26 the tubular portion 51A of the cam mechanism 51 will ride the top surface 76B and in doing so will lift the end of the blade tube 11. This lifting action will engage the tubular portion 518 with the depending control edge 81 of the guide 82. A similar condition will obtain simultaneously with respect to the blade plug 32 and its associated stationary contact assembly 27. Thus, the combined frictional resistance established between the two ends of the blade tube 11 and the associated cam mechanisms will provide a force which resists the movement of the blade tube 11 into the contact assemblies 26 and 27. As this occurs, the rotating insulator support 17 continues to drive the pedestal 102. This driving force is transmitted horizontally by the arm 111 to the cylindrical section 102 to provide a counterclockwise rotation of the blade tube 11 by means of the bolt 126. This rotation is opposed by the vertical reaction of the leaf spring 112. This reaction prevents blade rotation until the cam follower 51B contacts the cam surface 76C. However, the cylindrical section 122 moves in an arcuate path substantially tracing a path represented by the arcuate line identified by the reference number 137. To permit the combination of movements, the end of the leaf spring assembly 112 deflects allowing the cylindrical section 122 to move in its arcuate path of travel. At the same time that the leaf spring assembly 112 is deflecting, it is, of course, applying an upwardly acting,

force on the pivot bolt 126. As the blade tube 11 is rotated about its own axis by operation of the cam mechanism 51, sufficiently far enough so that the pivot bolt 126 is moved through the vertical plane, the leaf spring assembly 112 operates to apply a force to the end of pivot bolt 126 to urge the blade tube 11 in a counterclockwise direction. This action aides the cam mechanism 51 in effecting the final angular positioning of the blade plug 31 into the position it occupies asdepicted in FIG. 6.

In the embodiments of an invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a disconnect switch having a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis;

a blade plug having a relatively flattened or elliptical configuration carried in the end of said blade arm;

drive means operably connected to effect the bodily rotation of said blade assembly;

a stationary contact associated with said blade assembly and positioned to be engaged by said blade plug of said blade arm when said blade assembly is rotated bodily from an open to a closed position;

torque applying means including a cam follower on the axial end face of said blade plug, said cam follower being radially offset relative to the longitudinal axis of said blade plug; and,

said stationary contact includes a cam track in which said cam follower engages when the end of said blade arm is moved into engagement with said stationary contact by the bodily pivotal movement of said blade assembly, said cam track being config' ured in a manner that said cam follower in tracking in said cam track applies a torque to said blade arm to effect the rotation of said blade arm about its own axis as the bodily pivotal movementof said blade assembly continues;

whereby the blade plug of said arm is orientated into current carrying engagement with said stationary contact.

2. In a disconnect switch having a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis;

drive means operably connected to effect the bodily rotation of said blade assembly; x

a stationary contact associated with said blade assembly and positioned to be engaged by said blade arm of said blade assembly when said blade assembly is rotated bodily from an open to a closed position;

a housing carried by said drive means;

a leaf spring assembly having one end connected to said drive means and the opposite end in engagement with a connecting means carried by said blade arm, said leaf spring assembly being fulcrumed in said housing at a point between its ends;

torque applying means including a cam follower on the axial end face of said blade arm, said cam follower being radially offset relative to the longitudinal axis of said blade arm; and,

said stationary contact includes a cam track in which said cam follower engages when the end of said blade arm is moved into engagement with said stationary contact by the bodily pivotal movement of said blade assembly, said cam track being configured in a manner that said cam follower in tracking in said cam trackapplies a torque to said blade arm to effect the rotation of said blade arm about its own axis as the bodily pivotal movement of said blade assembly continues;

whereby the blade is orientated into current carrying engagement with said stationary contact.

3. A disconnect switch according to claim 2 wherein said connecting means includes a pivot bolt carried in said blade arm at an angle which is inclined from a vertical plane, said pivot bolt having one end extending outwardly of said blade arm;

a pivot support connected between the extending end of said pivot bolt and the adjacent end of said leaf spring assembly, said pivot support being constructed and arranged to present a knife edge which engages said leaf spring assembly to minimize friction therebetween and operable to transmit a force from said leaf spring assembly to said pivot bolt as said leaf spring assembly moves bodily with said drive means.

4. In a disconnect switch; a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis;

a contact blade plug on the end of said arm;

drive means operably connected to effect the bodily rotation of said blade assembly;

a stationary contact associated with said blade assembly and positioned to be engaged by said blade plug of said blade arm when said blade assembly is rotated bodily in a switch closing operation;

cam means on said stationary contact; a

a cam follower means on said blade plug of said blade arm in position to engage with said cam means on said stationary contact when said blade plug makes engagement with said stationary contact, said cam means being constructed and arranged to present cam guide means engageable by said cam follower means to effect angular positioning of said blade arm, said cam means also having further guide means engageable by said cam follower means to effect deceleration of said blade assembly and to effect rotation of said blade arm about its own axis to thereby effect good electrical engagement of said contact blade plug with said stationary contact, said cam means also operating to effect angular positioning rotation of said contact blade plug when said blade assembly is rotated bodily to open position.

5. In a disconnect switch;

a blade assembly supported for bodily rotation about an axis, said blade assembly having at least one blade arm extending in a plane transverse to the axis about which said assembly is bodily rotatable, said blade arm being supported by said blade assembly for rotation with said blade assembly and for independent rotation about its own axis;

a blade plug on the axial end of said blade arm;

a stationary contact having spaced apart resilient contact fingers adapted to be engaged by the edges of said blade plug to establish a good electrical connection therebetween;

a cam follower on the axial end of said blade plug;

cam means on said stationary contact adapted to be engaged by said cam follower upon the bodily rotation of said blade assembly in a switch closing operation, said cam means having cam surface means engageable by said cam follower to effect a positioning of said blade arm for entry into said stationary contact, said cam means also having another cam surface engageable by said cam follower to effect the rotation of said blade arm about its own axis to thereby rotate said blade plug into position wherein the edges of said blade plug make good electrical contact with the resilient contact fingers of said stationary contact, said cam means also operating to effect angular positioning rotation of said blade plug when said blade assembly is rotated bodily to open position.

6. A disconnect switch according to claim 5 wherein said cam means and said cam follower cooperate to effect rotational positioning movement of said blade arm upon the bodily rotation of said blade assembly in a switch opening operation to effect the angular positioning of said blade plug to a predetermined position for entry into said stationary contact in a subsequent switch closing operation.

7. A disconnect switch according to claim 5 wherein said cam follower has a portion offset relative to the axis of said blade arm to form a crank, said crank engaging said cam means to apply a torque to said blade arm to effect its rotation about its own axis.

8. A disconnect switch according to claim 7, wherein said cam means is provided with a cam surface which slopes upwardly from a horizontal plane;

said crank being positioned to engage said sloping cam surface as said blade assembly is moved bodily in a switch closing operation and thereby effect the rotation of said blade arm about its own axis to rotate said blade plug into electrical engagement with the resilient fingers of said stationary contact. 1: 

1. In a disconnect switch having a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis; a blade plug having a relatively flattened or elliptical configuration carried in the end of said blade arm; drive means operably connected to effect the bodily rotation of said blade assembly; a stationary contact associated with said blade assembly and positioned to be engaged by said blade plug of said blade arm when said blade assembly is rotated bodily from an open to a closed position; torque applying means including a cam follower on the axial end face of said blade plug, said cam follower being radially offset relative to the longitudinal axis of said blade plug; and, said stationary contact includes a cam track in which said cam follower engages when the end of said blade arm is moved into engagement with said stationary contact by the bodily pivotal movement of said blade assembly, said cam track being configured in a manner that said cam follower in tracking in said cam track applies a torque to said blade arm to effect the rotation of said blaDe arm about its own axis as the bodily pivotal movement of said blade assembly continues; whereby the blade plug of said arm is orientated into current carrying engagement with said stationary contact.
 2. In a disconnect switch having a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis; drive means operably connected to effect the bodily rotation of said blade assembly; a stationary contact associated with said blade assembly and positioned to be engaged by said blade arm of said blade assembly when said blade assembly is rotated bodily from an open to a closed position; a housing carried by said drive means; a leaf spring assembly having one end connected to said drive means and the opposite end in engagement with a connecting means carried by said blade arm, said leaf spring assembly being fulcrumed in said housing at a point between its ends; torque applying means including a cam follower on the axial end face of said blade arm, said cam follower being radially offset relative to the longitudinal axis of said blade arm; and, said stationary contact includes a cam track in which said cam follower engages when the end of said blade arm is moved into engagement with said stationary contact by the bodily pivotal movement of said blade assembly, said cam track being configured in a manner that said cam follower in tracking in said cam track applies a torque to said blade arm to effect the rotation of said blade arm about its own axis as the bodily pivotal movement of said blade assembly continues; whereby the blade is orientated into current carrying engagement with said stationary contact.
 3. A disconnect switch according to claim 2 wherein said connecting means includes a pivot bolt carried in said blade arm at an angle which is inclined from a vertical plane, said pivot bolt having one end extending outwardly of said blade arm; a pivot support connected between the extending end of said pivot bolt and the adjacent end of said leaf spring assembly, said pivot support being constructed and arranged to present a knife edge which engages said leaf spring assembly to minimize friction therebetween and operable to transmit a force from said leaf spring assembly to said pivot bolt as said leaf spring assembly moves bodily with said drive means.
 4. In a disconnect switch; a blade assembly bodily rotatable about an axis, said blade assembly including at least one blade arm supported by said blade assembly for independent rotation about its own axis; a contact blade plug on the end of said arm; drive means operably connected to effect the bodily rotation of said blade assembly; a stationary contact associated with said blade assembly and positioned to be engaged by said blade plug of said blade arm when said blade assembly is rotated bodily in a switch closing operation; cam means on said stationary contact; a cam follower means on said blade plug of said blade arm in position to engage with said cam means on said stationary contact when said blade plug makes engagement with said stationary contact, said cam means being constructed and arranged to present cam guide means engageable by said cam follower means to effect angular positioning of said blade arm, said cam means also having further guide means engageable by said cam follower means to effect deceleration of said blade assembly and to effect rotation of said blade arm about its own axis to thereby effect good electrical engagement of said contact blade plug with said stationary contact, said cam means also operating to effect angular positioning rotation of said contact blade plug when said blade assembly is rotated bodily to open position.
 5. In a disconnect switch; a blade assembly supported for bodily rotation about an axis, said blade assembly having at least one blade arm extending in a plane transverse To the axis about which said assembly is bodily rotatable, said blade arm being supported by said blade assembly for rotation with said blade assembly and for independent rotation about its own axis; a blade plug on the axial end of said blade arm; a stationary contact having spaced apart resilient contact fingers adapted to be engaged by the edges of said blade plug to establish a good electrical connection therebetween; a cam follower on the axial end of said blade plug; cam means on said stationary contact adapted to be engaged by said cam follower upon the bodily rotation of said blade assembly in a switch closing operation, said cam means having cam surface means engageable by said cam follower to effect a positioning of said blade arm for entry into said stationary contact, said cam means also having another cam surface engageable by said cam follower to effect the rotation of said blade arm about its own axis to thereby rotate said blade plug into position wherein the edges of said blade plug make good electrical contact with the resilient contact fingers of said stationary contact, said cam means also operating to effect angular positioning rotation of said blade plug when said blade assembly is rotated bodily to open position.
 6. A disconnect switch according to claim 5 wherein said cam means and said cam follower cooperate to effect rotational positioning movement of said blade arm upon the bodily rotation of said blade assembly in a switch opening operation to effect the angular positioning of said blade plug to a predetermined position for entry into said stationary contact in a subsequent switch closing operation.
 7. A disconnect switch according to claim 5 wherein said cam follower has a portion offset relative to the axis of said blade arm to form a crank, said crank engaging said cam means to apply a torque to said blade arm to effect its rotation about its own axis.
 8. A disconnect switch according to claim 7, wherein said cam means is provided with a cam surface which slopes upwardly from a horizontal plane; said crank being positioned to engage said sloping cam surface as said blade assembly is moved bodily in a switch closing operation and thereby effect the rotation of said blade arm about its own axis to rotate said blade plug into electrical engagement with the resilient fingers of said stationary contact. 